scholarly journals Advancing MıNNLOPS to diboson processes: Zγ production at NNLO+PS

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Daniele Lombardi ◽  
Marius Wiesemann ◽  
Giulia Zanderighi
Keyword(s):  
Hard Scattering ◽  
A Posteriori ◽  
Leading Order ◽  
Spin Correlations ◽  
Shell Effects ◽  
Atlas Data ◽  
Hadronic Collisions ◽  
Good Agreement ◽  
The Way

Abstract We consider Zγ production in hadronic collisions and present the first computation of next-to-next-to-leading order accurate predictions consistently matched to parton showers (NNLO+PS). Spin correlations, interferences and off-shell effects are included by calculating the full process pp → ℓ+ℓ−γ. We extend the recently developed MiNNLOPS method to genuine 2 → 2 hard scattering processes at the LHC, which paves the way for NNLO+PS simulations of all diboson processes. This is the first 2 → 2 NNLO+PS calculation that does not require an a-posteriori multi-differential reweighting. We find that both NNLO corrections and matching to parton showers are crucial for an accurate simulation of the Zγ process. Our predictions are in very good agreement with recent ATLAS data.

scholarly journals W+W− production at NNLO+PS with MINNLOPS

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Daniele Lombardi ◽  
Marius Wiesemann ◽  
Giulia Zanderighi
Keyword(s):  
Cross Sections ◽  
Spline Interpolation ◽  
A Posteriori ◽  
Loop Contribution ◽  
Spin Correlations ◽  
Shell Effects ◽  
Evaluation Time ◽  
Order Of Magnitude ◽  
Hadronic Collisions ◽  
Good Agreement

Abstract We consider W+W− production in hadronic collisions and present the computation of next-to-next-to-leading order accurate predictions consistently matched to parton showers (NNLO+PS) using the MiNNLOPS method. Spin correlations, interferences and off-shell effects are included by calculating the full process pp → e+νeμ−$$ \overline{\nu} $$ ν ¯ μ. This is the first NNLO+PS calculation for W+W− production that does not require an a-posteriori multi-differential reweighting. The evaluation time of the two-loop contribution has been reduced by more than one order of magnitude through a four-dimensional cubic spline interpolation. We find good agreement with the inclusive and fiducial cross sections measured by ATLAS and CMS. Both NNLO corrections and matching to parton showers are important for an accurate simulation of the W+W− signal, and their matching provides the best description of fully exclusive W+W− events to date.

scholarly journals Dynamical Grooming meets LHC data

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Paul Caucal ◽  
Alba Soto-Ontoso ◽  
Adam Takacs
Keyword(s):  
Parton Shower ◽  
Probability Distributions ◽  
Opening Angle ◽  
Leading Order ◽  
Infra Red ◽  
Hadronic Collisions ◽  
Perturbative Corrections ◽  
Good Agreement ◽  
Double Logarithm

Abstract In this work, we analyse the all-orders resummation structure of the momentum sharing fraction, zg, opening angle, θg, and relative transverse momentum, kt,g, of the splitting tagged by the Dynamical Grooming procedure in hadronic collisions. We demonstrate that their resummation does non-exponentiate and it is free of clustering logarithms. Then, we analytically compute the probability distributions of (zg, θg, kt,g) up to next-to-next-to-double logarithm accuracy (N2DL) in the narrow jet limit, including a matching to leading order in αs. On the phenomenological side, we perform an analytic-to-parton level comparison with Pythia and Herwig. We find that differences between the analytic and the Monte-Carlo results are dominated by the infra-red regulator of the parton shower. Further, we present the first analytic comparison to preliminary ALICE data and highlight the role of non-perturbative corrections in such low-pt regime. Once the analytic result is corrected by a phenomenologically determined non-perturbative factor, we find very good agreement with the data.

scholarly journals Experimental Methods for Measuring the Viscous Friction Coefficient in Hydraulic Spool Valves

2021 ◽  
Vol 13 (13) ◽  
pp. 7174
Author(s):  
Massimo Rundo ◽  
Paolo Casoli ◽  
Antonio Lettini
Keyword(s):  
Friction Coefficient ◽  
Viscous Friction ◽  
Experimental Tests ◽  
Experimental Methods ◽  
Displacement Transducer ◽  
A Posteriori ◽  
Displacement Control ◽  
Spool Valves ◽  
The University ◽  
Good Agreement

In hydraulic components, nonlinearities are responsible for critical behaviors that make it difficult to realize a reliable mathematical model for numerical simulation. With particular reference to hydraulic spool valves, the viscous friction coefficient between the sliding and the fixed body is an unknown parameter that is normally set a posteriori in order to obtain a good agreement with the experimental data. In this paper, two different methodologies to characterize experimentally the viscous friction coefficient in a hydraulic component with spool are presented. The two approaches are significantly different and are both based on experimental tests; they were developed in two distinct laboratories in different periods of time and applied to the same flow compensator of a pump displacement control. One of the procedures was carried out at the Fluid Power Research Laboratory of the Politecnico di Torino, while the other approach was developed at the University of Parma. Both the proposed methods reached similar outcomes; moreover, neither method requires the installation of a spool displacement transducer that can significantly affect the results.

scholarly journals Trauma and Sacrifice in Divided Communities: The Sacralisation of the Victims of Terrorism in Spain

Religions ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 104
Author(s):  
Eliana Alemán ◽  
José Pérez-Agote
Keyword(s):  
Human Life ◽  
Traumatic Events ◽  
The State ◽  
A Posteriori ◽  
Institutional Discourse ◽  
Divided Societies ◽  
The Us ◽  
Definition Of ◽  
Public Demonstrations ◽  
The Way

This work aims to show that the sacrificial status of the victims of acts of terrorism, such as the 2004 Madrid train bombings (“11-M”) and ETA (Basque Homeland and Liberty) attacks in Spain, is determined by how it is interpreted by the communities affected and the manner in which it is ritually elaborated a posteriori by society and institutionalised by the state. We also explore the way in which the sacralisation of the victim is used in socially and politically divided societies to establish the limits of the pure and the impure in defining the “Us”, which is a subject of dispute. To demonstrate this, we first describe two traumatic events of particular social and political significance (the case of Miguel Ángel Blanco and the 2004 Madrid train bombings). Secondly, we analyse different manifestations of the institutional discourse regarding victims in Spain, examining their representation in legislation, in public demonstrations by associations of victims of terrorism and in commemorative “performances” staged in Spain. We conclude that in societies such as Spain’s, where there exists a polarisation of the definition of the “Us”, the success of cultural and institutional performances oriented towards reparation of the terrorist trauma is precarious. Consequently, the validity of the post-sacrificial narrative centring on the sacred value of human life is ephemeral and thus fails to displace sacrificial narratives in which particularist definitions of the sacred Us predominate.

Magnetic Phase Transition in MnSi Based on the First Principle Calculations of Electronic Structure and Spin Fluctuation Theory

2019 ◽  
Vol 289 ◽  
pp. 198-204
Author(s):  
Aleksandr Povzner ◽  
Tatyana A. Nogovitsyna ◽  
Arkadij G. Volkov ◽  
Tagir Nuretdinov
Keyword(s):  
Phase Transition ◽  
Electronic Structure ◽  
Magnetic Phase Transition ◽  
Magnetic Phase ◽  
Spin Fluctuation ◽  
Fluctuation Theory ◽  
Ministry Of Education ◽  
Spin Correlations ◽  
The Russian Federation ◽  
Good Agreement

Based on the spin-fluctuation theory and LSDA + U + SO-calculations of the electronic structure, the spin states arising in the region of the magnetic phase transition in the helicoidal ferromagnet MnSi are studied. Within the framework of the stated model of the electronic structure, a temperature dependence of the homogeneous magnetic susceptibility is obtained near the temperature of the magnetic phase transition, which is in good agreement with experiment. At the temperature of the transition to the paramagnetic state, the left chirality vanishes, and spin correlations arise with a radius equal to the length of the spin helix, which then decreases with temperature. The results were obtained within the framework of the assignment of the Ministry of Education and Science of the Russian Federation, contract 3.9521.2017 / 8.9

SPIN CORRELATIONS OF THE MAGNETORESISTIVE BILAYER MANGANITE La1.2Sr1.8Mn2O7

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3820-3822
Author(s):  
S. Rosenkranz ◽  
R. Osborn ◽  
J. F. Mitchell ◽  
L. Vasiliu-Doloc ◽  
J. W. Lynn ◽  
...  
Keyword(s):  
Colossal Magnetoresistance ◽  
Double Exchange ◽  
Hole Mobility ◽  
Ferromagnetic Transition ◽  
Double Exchange Interaction ◽  
Metal Insulator ◽  
Spin Correlations ◽  
Paramagnetic Region ◽  
X Ray Scattering ◽  
Good Agreement

We review our recent neutron and X-ray scattering studies of the 40% hole doped bilayer manganite La 1.2 Sr 1.8 Mn 2 O 7, which exhibits colossal magnetoresistance above the ferromagnetic transition at T C~113 K. In the paramagnetic region, static diffuse scattering reveals the existence of correlated charges. However, the good agreement of the in-plane spin correlations with the conventional model for quasi two-dimensional XY magnets indicates that the metal-insulator transition is driven by the growth of magnetic correlations. Across the transition, the competition between antiferromagnetic superexchange and ferromagnetic double exchange, observed as canted correlations between spins in neighboring layers within each bilayer, is strongly reduced, indicating a direct link of the double exchange interaction to the hole mobility.

scholarly journals Damped Ly α absorbers and atomic hydrogen in galaxies: the view of the GAEA model

2020 ◽  
Vol 497 (2) ◽  
pp. 2469-2485 ◽  
Author(s):  
Serafina Di Gioia ◽  
Stefano Cristiani ◽  
Gabriella De Lucia ◽  
Lizhi Xie
Keyword(s):  
State Of The Art ◽  
Mass Function ◽  
Distribution Model ◽  
Analytic Model ◽  
A Posteriori ◽  
The Galaxy ◽  
Low Mass ◽  
Halo Occupation Distribution ◽  
Metallicity Distribution ◽  
Good Agreement

ABSTRACT Using the GAEA semi-analytic model, we analyse the connection between Damped Ly α systems (DLAs) and H i in galaxies. Our state-of-the-art semi-analytic model is tuned to reproduce the local galaxy H i mass function, and that also reproduces other important galaxy properties, including the galaxy mass–gas metallicity relation. To produce catalogues of simulated DLAs we throw 105 random lines of sight in a composite simulated volume: dark matter haloes with log$(\frac{M_{200}}{ {\rm M}_{\odot }}) \ge 11.5$ are extracted from the Millennium Simulation, while for $9.2 \le \log (\frac{M_{200}}{ \mathrm{M}_{\odot }})\lt 11.5$ we use the Millennium II, and for $8 \le \log (\frac{M_{200}}{\mathrm{M}_{\odot }}) \lt 9.2$ a halo occupation distribution model. At 2 < z < 3, where observational data are more accurate, our fiducial model predicts the correct shape of the column density distribution function, but its normalization falls short of the observations, with the discrepancy increasing at higher redshift. The agreement with observations is significantly improved increasing both the H i masses and the disc radii of model galaxies by a factor of 2, as implemented ‘a posteriori’ in our 2M−2R model. In the redshift range of interest, haloes with $M_{200} \ge {10}^{11} \, \mathrm{M}_{\odot }$ give the major contribution to ΩDLA, and the typical DLA host halo mass is $\sim \!{10}^{11} \, \mathrm{M}_{\odot }$. The simulated DLA metallicity distribution is in relatively good agreement with observations, but our model predicts an excess of DLAs at low metallicities. Our results suggest possible improvements for the adopted modelling of the filtering mass and metal ejection in low-mass haloes.

GROUND STATE PROPERTIES OF EXTREME NEUTRON RICH ISOTOPES OBSERVED: A RELATIVISTIC MEAN FIELD APPROACH

2011 ◽  
Vol 20 (11) ◽  
pp. 2293-2303 ◽  
Author(s):  
PROVASH MALI
Keyword(s):  
Ground State ◽  
Mean Field ◽  
Mass Region ◽  
Binding Energies ◽  
Droplet Model ◽  
Shell Effects ◽  
Relativistic Mean Field ◽  
Ground State Properties ◽  
Neutron Rich Isotopes ◽  
Good Agreement

The ground state properties namely the binding energy, the root mean square (rms) radius (neutron, proton and charge) and the deformation parameter of 45 newly identified neutron-rich isotopes in the A~71–152 mass region have been predicted in the relativistic mean filed (RMF) framework along with the Bardeen–Cooper–Schrieffer (BCS) type of pairing. Validity of the RMF results with the NL3 effective force are tested for odd-A Zn and Rh isotopic chains without taking the time reversal symmetry breaking effects into consideration. The RMF prediction on the binding energies are in good agreement with the empirical/finite-range droplet model calculation. The shell effects on the rms radii of odd-A Zn and Rh isotopes are nicely reproduced. The possibility of shape-coexistence in the newly identified nuclei is discussed.

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